UM3 "pausing" between Layers, homing to back right and staying there until user interaction

[unccheezy 1]

Not sure what is going on. Finally got the printer printing with PVA and PLA. Now for some reason between layers the machine is homing to the back right and staying there until I press "pause" then "unpause." Then it will do another layer and do the same thing. This is happening between each layer that I print with both PVA and PLA. Printing with PLA works just fine. I printed 3DBenchy in just PLA without any issues.

I don't have any plugins enabled. I will post the GCode to see if there are any issues there. I can also get logs off the machine. Has anyone seen this behavior?

I also rebooted machine to see but it's still the same.

Using default profiles on CURA 2_4(beta) and the 2_3_1(released) app. Both have same issue. I will take some video of this today.

[unccheezy 1]

I should also note that the machine isn't technically in the "paused" state. I actually have to hit the pause button, then unpause it. It just won't actually continue printing.

[unccheezy 1]

Here is the gcode I exported https://gist.github.com/shawnkirsch/0c531832763d6ff165ee7ebaa91f84ae

[unccheezy 1]

 

uploading now...

[tomnagel 126]

How long does it sit there? Indefinitely, unless you pause/unpause?

What is going on:

When one nozzle is printing, the other nozzle is lowered in temperature. This is to prevent the unused material from degrading.

Before the printing nozzle is ready with its layer, the other nozzle is heated. This is so timed that at the switching time, the right temperature is reached.

All this is done in Cura, so in the gcode.

But this is timed, based on a simple model. Printing temperature might be reached a little too late or too early.

So it is normal that after switching, the nozzle needs some time to reach the printing temperature, should be less than 30 seconds.

If it sits there longer, something is not right.

If you would like to diagnose yourself you can see what is happening with setpoints and actual temperatures on /temperature.html

If you don't, contact your reseller.

One specific question: do you see a white silicon rubber flap on the bottom of your print head, and does it seem to be well installed? Without this rubber flap, the nozzle is not always able to reach the right temperature.

[tomnagel 126]

I'm interested in the log files. If you want, please dump the logs to USB drive (system->maintenance->diagnosis) and send them to t.nagel@ultimaker.com

[unccheezy 1]

 

@tomnagel  I think you nailed it.  It was doing the first layer then sitting in that corner until I came back ~1 hour later.  The other day we had a massive print fail where PLA got stuck over the entire outside of the cover and when it got cleaned up we must have lost the o'ring on the BB core.  What kind of o'ring is this?  I don't see any mention of it.  Could you ship us a new one?  I have emailed you the logs.

[tomnagel 126]

@tomnagel  I think you nailed it.  It was doing the first layer then sitting in that corner until I came back ~1 hour later.  The other day we had a massive print fail where PLA got stuck over the entire outside of the cover and when it got cleaned up we must have lost the o'ring on the BB core.  What kind of o'ring is this?  I don't see any mention of it.  Could you ship us a new one?  I have emailed you the logs.

 

But the missing ring cannot explain this waiting behavior. Is there or is there not a rubber flap on the bottom of the print head? It is (should be) located in the bracket of the front fan, the bracket that you open when you want to remove a print core.

I received your log, thank you. We'll have a look at it.

[Daid 306]

I just looked at the log files you send it. (This really helps)

Your left PrintCore is trying to heatup to 200C, but it does not reach a temperature above 196C.

Can you try heating up the PrintCore to 240C, and checking which temperature it reaches?

You should have a 2nd AA PrintCore, try swapping this other AA core for the left one. If this fixes the problem, then your primary AA core is faulty.

[unccheezy 1]

@tomnagel still not sure what you are speaking about, so I'm posting a few photos I took.

@daid Heated AA core to 240, printout said 240. Maybe only problem when power is going to both cores?

[unccheezy 1]

I would like to note that I can print just PLA core only no problem.

[Daid 306]

I just fixed a firmware bug where the printer wouldn't heatup properly. But I'm not entirely convinced that you are having this exact bug.

You can check if this bug is the case by tuning 1C offset to the temperature when this stop happens. If it continues then, then you are experiencing this bug (and the bug is them more critical then I expected)

Another thing that could be happening is that you are hitting power limits. There is a special webpage on the printer, reachable with http://[ip address]/temperature.html this gives a readout of all the current temperatures and heater outputs. It might give more insight into this issue as well.

[unccheezy 1]

So I did some testing. I have a hunch that the issue is when both of the hot ends are at 200 and 215. That's when the AA core doesn't heatup. it will stay around 197 and 213 respectively.

I did try your fix and that sometimes made it instantly begin the next later, and sometimes not. It still stopped during the next layer.

Do you think it's the print? Can you guys point me to some good test prints for PLA and PVA?

Here is a pic of the temperature.html page. Is the bed power supposed to be fluctuating that much?

[fbrc8-erin 272]

It's a little hard to tell in your photos, but does your silicone piece look like this?

 

@tomnagel still not sure what you are speaking about, so I'm posting a few photos I took.

@daid Heated AA core to 240, printout said 240.  Maybe only problem when power is going to both cores?

 

[neotko 1,417]

It's a little hard to tell in your photos, but does your silicone piece look like this?

 

@tomnagel still not sure what you are speaking about, so I'm posting a few photos I took.

@daid Heated AA core to 240, printout said 240.  Maybe only problem when power is going to both cores?

 

 

Nicely spotted! He actually doesn't have silicon piece at all! Check the photos, you can see through.

That explains why the heat with the fans on at layer 2 can't reach the temp target.

[unccheezy 1]

It does NOT look like that OMG!?!?!?! I don't ever remember that being in our printer.

[fbrc8-erin 272]

It would have been in there when the printer arrived, but there's a good chance it never made it back in after the flood you mentioned earlier. Failed prints can cause the piece to tear, or to come out. It would have been really easy to miss.

It looks like you're located in the US, so if you want to contact Support@fbrc8.com, we can get a replacement silicone piece sent out to you on Monday. We'll need your name, address, and serial number number. It would also help to reference this post in your email since the troubleshooting has already been done.

 

It does NOT look like that OMG!?!?!?!  I don't ever remember that being in our printer.

 

[unccheezy 1]

Thanks for all the help everyone. Great diagnosis's. With the silicon parts I was able to get back to printing. One question left is does this look right? It seems to be hanging down a little bit over the nozzles.

[SandervG 1,521]

It looks alright